Breast Health

Women Quit Breast Cancer Drugs Over Side Effects

Drugs that help prevent the recurrence of breast cancer can cause such unpleasant side effects that many women stop taking them.

Researchers at Northwestern University in Chicago looked at drugs called aromatase inhibitors (AIs), which stop the production of estrogen. These drugs - including anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara) - typically are used after treatment for estrogen-sensitive breast cancer to keep the cancer from recurring.

The National Cancer Institute says that the usual length of treatment with AIs is five years.

Two-year study

The study, presented at a breast cancer symposium sponsored by the American Association for Cancer Research, followed for two years nearly 700 postmenopausal women with estrogen-sensitive breast cancer.

After three months, about a third of the women had severe joint pain, about 30 percent had hot flashes, nearly one-quarter had decreased libido, 15 to 24 percent had fatigue, nearly 20 percent had night sweats, and about 15 percent had anxiety. Other symptoms included weight gain, breast sensitivity, mood swings, and feeling bloated, irritable, or nauseous.

The longer the women used the drugs, the greater the number of women who reported side effects.

Stopped medication

As a result of the side effects, 36 percent of the women stopped treatment before an average of just over four years. Of this group, 10 percent had quit after two years, and the remainder quit between 25 months and about four years.

Women were more likely to stop taking the drugs early if they still had residual side effects from recent chemotherapy or radiation therapy.

Response to results

"These findings can help us identify women at risk for quitting the therapy, counsel them about the importance of staying on it, and provide treatment for troubling side effects," says lead researcher Lynne Wagner, Ph.D.

Bu the results also point out that doctors need to be more aware of a drug's side effects and take steps to ease problems.

"[Doctors] give patients a drug they hope will help them, so they have a motivation to underrate the negative effects," Dr. Wagner says. "Patients don't want to be complainers and don't want their doctor to discontinue treatment. So no one knew how bad it really was for patients."

Always talk with your health care provider to find out more information.

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